The influence of degradation phenomena on collapse modes in prestressed concrete beams

Abstract

Abstract:The static capacities of reinforced and prestressed concrete beams are characterised through their failure modes, which describe the internal force redistribution as well as the kinematic evolution which leads to the collapse of the structure. For a given structural element, a change in material and/or sectional characteristics due, for instance, to damaging effects induced by environmental aggressive agents, may change the element behaviour. In this paper, a computational approach, suitable to deal with the analysis of R.C. and P.C. concrete elements with steel bars and/or tendons subjected to corrosion is presented. The effects of the diffusion of aggressive agents, of the onset and of the development the corrosion state in the reinforcement and the corresponding mechanical response are studied. The damage development and the mechanical behaviours are dealt as coupled phenomena. A set of comparative applications shall demonstrate how in P.C. beams, the corrosion could switch a collapse of flexural type to one of shear type.

Monte Carlo Analysis for the Blast Resistance Design and Assessment of a Reinforced Concrete Wall

“…Future studies could take into account the deterioration of the materials of the different components in the fragility curves, during the entire life cycle -see for example [17]. Moreover, soft-computing methods could be implemented for the more efficient treatment of the uncertainties [18].…”

Influence of degradation at the base of a support post in a collapse of an old guardrail: A forensic analysis

“…The atmosphere and the salt used on the roads during the winter can trigger corrosion phenomena on the structure of the guardrail, putting at risk its functionality [20]. And in fact it has been shown that, in certain structures, the presence of corrosion can not only reduce the strength capacity of the structure but can also lead to a change in the behaviour of collapse [32][33][34]. Corrosion may also lead to a decrease in structural strength, causing a progressive collapse of the structure similar to that which can occur in a suspension bridge after the collapse of a suspension cable [13,24].…”